[Effects of solution of dry powder of ShenSongYangXin capsule on sodium current and L-type calcium current in ventricular myocytes: experiment with guinea pig]

Abstract

Objective: To investigate the effects of dry powder of ShenSongYangXin capsule on sodium current (I(Na)) and L-type calcium current (I(Ca, L)) in ventricular myocytes.

Methods: Ventricular myocytes were isolated from guinea pig. Solution of the dry powder of ShenSongYangXin capsule of the concentrations of 1%, 0.5%, and 0.25% was added into the suspension of the myocytes. Whole cell patch-clamp technique was used to detect the I(Na) and I(Ca, L) in the ventricular myocytes.

Result: ShenSongYangXin decreased the peak I(Na) from 27.2 +/- 5.4 (pA/pF) to 14.9 +/- 2.8 (pA/pF), with a decrease rate of 44.8% +/- 7.7% (n = 5, P < 0.05). The solution of dry powder of ShenSongYangXin of the concentrations of 1%, 0.5%, and 0.25% decreased the peak L-type calcium channel current (I(ca, L)) significantly in a concentration dependent manner with the reduction rates of 50.7% +/- 5.6%, 44.8% +/- 6.5%, and 19.2% +/- 1.1% respectively (n = 5, all P < 0.05). ShenSongYangXin shifted up both the I approximately 1V curve of I(Na) and that of I(Ca, L), while their active, peak and reverse potentials didn't change.

Conclusion: ShenSongYangXin blocks both I(Na) and I(Ca, L), which may contributes to some of its antiarrhythmic effect.